Restify

Restify is an hypermedia REST client that does parallel, concurrent and keep-alive requests by default.

Restify scans Link headers and returned resource for links and relations to other resources, represented as RFC6570 URI Templates, and exposes those to the developer.

Restify can be used to consume hypermedia REST APIs (like GitHubs), to build a site-specific library or to use within your own backend services.

Restify is build upon the following libraries:

• concurrent-ruby
• addressable
• typhoeus

The HTTP adapters are mostly run in a background thread and may not survive mid-application forks.

Restify includes processors to parse responses and to extract links between resources. The following formats are can be parsed:

• JSON
• MessagePack

Links are extracted from

• HTTP Link header
• Github-style relations in payloads

Planned features

• HTTP cache
• API versions via header
• Content-Type and Language negotiation
• Processors for JSON-HAL, etc.

Installation

Add it to your Gemfile or install it manually: $ gem install restify

Usage

Create new Restify object. It essentially means to request some start-resource usually the "root" resource:

client = Restify.new('https://api.github.com').get.value
# => {"current_user_url"=>"https://api.github.com/user",
#     "current_user_authorizations_html_url"=>"https://github.com/settings/connections/applications{/client_id}",
# ...
#     "repository_url"=>"https://api.github.com/repos/{owner}/{repo}",
# ...

We are essentially requesting 'http://api.github.com' via HTTP get. get is returning an Promise, similar to Java's Future. The value call resolves the returned Promise by blocking the thread until the resource is actually there. value! will additionally raise errors instead of returning nil. You can chain handlers using the then method. This allows you to be build a dependency chain that will be executed when the last promise is needed.

As we can see GitHub returns us a field repository_url with a URI template. Restify automatically scans for *_url fields in the JSON response and exposes these as relations. It additionally scans the HTTP Header field Link for relations like pagination.

We can now use the relations to navigate from resource to resource like a browser from one web page to another page.

repositories = client.rel(:repository)
# => #<Restify::Relation:0x00000005548968 @context=#<Restify::Context:0x007f6024066ae0 @uri=#<Addressable::URI:0x29d8684 URI:https://api.github.com>>, @template=#<Addressable::Template:0x2aa44a0 PATTERN:https://api.github.com/repos/{owner}/{repo}>>

This gets us the relation named repository that we can request now. The usual HTTP methods are available on a relation:

    def get(params = {})
      request :get, nil, params
    end

    def delete(params = {})
      request :delete, nil, params
    end

    def post(data = {}, params = {})
      request :post, data, params
    end

    def put(data = {}, params = {})
      request :put, data, params
    end

    def patch(data = {}, params = {})
      request :patch, data, params
    end

URL templates can define some parameters such as {owner} or {repo}. They will be expanded from the params given to the HTTP method method.

Now send a GET request with some parameters to request a specific repository:

repo = repositories.get(owner: 'jgraichen', repo: 'restify').value

Now fetch a list of commits for this repo and get this first one:

commit = repo.rel(:commits).get.value.first

And print it:

puts "Last commit: #{commit['sha']}"
puts "By #{commit['commit']['author']['name']} <#{commit['commit']['author']['email']}>"
puts "#{commit['commit']['message']}"

See commented example in main spec spec/restify_spec.rb or in the examples directory.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit specs for your feature so that I do not break it later
4. Commit your changes (git commit -am 'Add some feature')
5. Push to the branch (git push origin my-new-feature)
6. Create new Pull Request

License

Copyright (C) 2014-2018 Jan Graichen

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program. If not, see http://www.gnu.org/licenses/.